A variety of surgical instruments include an end effector having a blade element that vibrates at ultrasonic frequencies to cut and/or seal tissue (e.g., by denaturing proteins in tissue cells). These instruments include piezoelectric elements that convert electrical power into ultrasonic vibrations, which are communicated along an acoustic waveguide to the blade element. The precision of cutting and coagulation may be controlled by the surgeon's technique and adjusting the power level, blade edge, tissue traction and blade pressure.
Examples of ultrasonic surgical instruments include the HARMONIC ACE® Ultrasonic Shears, the HARMONIC WAVE® Ultrasonic Shears, the HARMONIC FOCUS® Ultrasonic Shears, and the HARMONIC SYNERGY® Ultrasonic Blades, all by Ethicon Endo-Surgery, Inc. of Cincinnati, Ohio. Further examples of such devices and related concepts are disclosed in U.S. Pat. No. 5,322,055, entitled “Clamp Coagulator/Cutting System for Ultrasonic Surgical Instruments,” issued Jun. 21, 1994, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 5,873,873, entitled “Ultrasonic Clamp Coagulator Apparatus Having Improved Clamp Mechanism,” issued Feb. 23, 1999, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 5,980,510, entitled “Ultrasonic Clamp Coagulator Apparatus Having Improved Clamp Arm Pivot Mount,” filed Oct. 10, 1997, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 6,325,811, entitled “Blades with Functional Balance Asymmetries for use with Ultrasonic Surgical Instruments,” issued Dec. 4, 2001, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 6,773,444, entitled “Blades with Functional Balance Asymmetries for Use with Ultrasonic Surgical Instruments,” issued Aug. 10, 2004, the disclosure of which is incorporated by reference herein; and U.S. Pat. No. 6,783,524, entitled “Robotic Surgical Tool with Ultrasound Cauterizing and Cutting Instrument,” issued Aug. 31, 2004, the disclosure of which is incorporated by reference herein.
Still further examples of ultrasonic surgical instruments are disclosed in U.S. Pub. No. 2006/0079874, entitled “Tissue Pad for Use with an Ultrasonic Surgical Instrument,” published Apr. 13, 2006, now abandoned, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2007/0191713, entitled “Ultrasonic Device for Cutting and Coagulating,” published Aug. 16, 2007, now abandoned, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2007/0282333, entitled “Ultrasonic Waveguide and Blade,” published Dec. 6, 2007, now abandoned, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2008/0200940, entitled “Ultrasonic Device for Cutting and Coagulating,” published Aug. 21, 2008, now abandoned, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2009/0105750, entitled “Ergonomic Surgical Instruments,” published Apr. 23, 2009, issued as U.S. Pat. No. 8,623,027 on Jan. 7, 2014, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2010/0069940, entitled “Ultrasonic Device for Fingertip Control,” published Mar. 18, 2010, issued as U.S. Pat. No. 9,023,071 on May 5, 2015,the disclosure of which is incorporated by reference herein; and U.S. Pub. No. 2011/0015660, entitled “Rotating Transducer Mount for Ultrasonic Surgical Instruments,” published Jan. 20, 2011, issued as U.S. Pat. No. 8,461,744 on Jun. 11, 2013, the disclosure of which is incorporated by reference herein; and U.S. Pub. No. 2012/0029546, entitled “Ultrasonic Surgical Instrument Blades,” published Feb. 2, 2012, issued as U.S. Pat. No. 8,591,536 on Nov. 26, 2013, the disclosure of which is incorporated by reference herein.
Some of ultrasonic surgical instruments may include a cordless transducer such as that disclosed in U.S. Pub. No. 2012/0112687, entitled “Recharge System for Medical Devices,” published May 10, 2012, issued as U.S. Pat. No. 9,381,058 on Jul. 5, 2016, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2012/0116265, entitled “Surgical Instrument with Charging Devices,” published May 10, 2012, now abandoned, the disclosure of which is incorporated by reference herein; and/or U.S. Pat. App. No. 61/410,603, filed Nov. 5, 2010, entitled “Energy-Based Surgical Instruments,” the disclosure of which is incorporated by reference herein.
Additionally, some ultrasonic surgical instruments may include an articulating shaft section. Examples of such ultrasonic surgical instruments are disclosed in U.S. patent application Ser. No. 13/538,588, filed Jun. 29, 2012, issued as U.S. Pat. No. 9,393,037on Jul. 19, 2016, entitled “Surgical Instruments with Articulating Shafts,” the disclosure of which is incorporated by reference herein; and U.S. patent application Ser. No. 13/657,553, filed Oct. 22, 2012, issued as U.S. Pat. No. 9,095,367on Aug. 4, 2015, entitled “Flexible Harmonic Waveguides/Blades for Surgical Instruments,” the disclosure of which is incorporated by reference herein.
Many ultrasonic surgical instruments utilize clamp pads to compress tissue against the ultrasonic blade to improve coaptation of blood vessels and improve hemostasis. Current instruments use thermoset grades of materials such as Polytetrafluoroethylene (PTFE). Two such devices are Sonocision® manufactured by Covidien®, Dublin, Ireland and Sonosurg® manufactured by Olympus®, Center Valley Pa. In these devices a unitary clamp arm pad formed from PTFE is used. Although this material provides significant lubricity to the pad, it does have the drawback of being less robust against heat. As such, the tissue pads in these devices do not provide as long a life as materials made from materials with higher melt temperatures and these pads can be cut through prematurely, especially when used in an abuse mode where there is no tissue between the clamp arm pad and the ultrasonic blade. Although higher melt temperature materials are available, these are not used in these unitary pad designs as they do not provide sufficient lubricity and cause the ultrasonic blade to become excessively hot towards its distal end when the ultrasonic blade is in direct contact with the clamp arm pad.
A different type of clamp arm pad design is employed in Harmonic ACE®, manufactured by Ethicon Endo-Surgery®, Cincinnati Ohio. This ultrasonic surgical shears device utilizes a two part clamp arm pad with the distal section made from PTFE and the proximal portion made from various Polyimide (PI) materials. Utilization of the two part design allows for the lower amplitude portion of the ultrasonic blade to contact the lower lubricity PI pad material, while the higher amplitude portion of the ultrasonic blade contacts the higher lubricity PTFE pad material. In this way the inherent high temperature resistance properties of the PI material can be used to provide longer pad life while not generating excessive heat since the amplitude and hence the velocity of the ultrasonic blade portion in contact with the PI pad are low enough that excessive frictional heat is not generated. The PTFE pad portion in this design is in contact with the higher amplitude and hence higher velocity portion of the ultrasonic blade; however the high lubricity of the PTFE material prevents excessive frictional heat from being generated at the pad-blade interface. The drawback of the two part pad design is that it requires the instrument to go through additional manufacturing processes to “burn-in” the pad material so that it properly interfaces with the ultrasonic blade along the entire length of both clamp arm pads. In addition, PI and PTFE materials have different material hardness which makes a two part pad design more susceptible to the softer PTFE material being damaged during use such that the interface surface between the ultrasonic blade and the two pads becomes inconsistent at the point where the PI and PTFE pads are joined. This in turn can cause the instrument to become less effective at cutting tissue in this area of the clamp arm pad, ultrasonic blade interface.
Although a unitary pad design with sufficient heat resistance is preferable, it was long believed that it was not possible to create a single clamp arm tissue pad made from a single material that provided both the necessary temperature resistance and the necessary lubricity to be useful in an ultrasonic surgical shears design. In addition, it was not believe to be possible to develop an injection moldable material that provided the necessary temperature resistance to be used in these designs. There is therefore still a need for a clamp arm pad material that provides sufficient lubricity and temperature resistance to be used as a unitary pad material in these types of ultrasonic surgical instruments. There is also a need for clamp arm pad materials that can be more easily processed to allow for injection molding of the clamp arm-clamp arm pad combination or over molding of a clamp arm pad material onto a clamp arm substrate.
While several surgical instruments and systems have been made and used, it is believed that no one prior to the inventors has made or used the invention described in the appended claims.
The drawings are not intended to be limiting in any way, and it is contemplated that various embodiments of the technology may be carried out in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present technology, and together with the description serve to explain the principles of the technology; it being understood, however, that this technology is not limited to the precise arrangements shown.